C4 LS1

So here is a little background. I did a swap into my 93 vette for an ls1. I have a psi harness all wired in. The Injectors are firing. It has spark plenty of air and no codes are being thrown. Any input will help I have done a lot of troubleshooting and I just can't seem to find a problem. I did however notice the spark is not a nice blue it's more of an orange, I don't really know if it is supposed to be that way.

LSCha0s

iTrader: (4)

Has the VATS been tuned out of the PCM? I would contact PSI about it.

C4 LS1

Yes I had the vats tuned out by psi and all the emissions removed.

lizeec

iTrader: (57)

What was your method of verifying the injectors are pulsing, have you tried a squirt of starting fluid in the intake? If engine has been sitting awhile the injectors can be stuck, it is a common problem on junkyard engines.

kossuth

iTrader: (12)

I wouldn't use starting fluid but that's me, seen enough damaged motors from folks getting too carried away. Anyways, yes the fuel injectors being gummed is possible, but I do feel that it is relately remote that they all wouldn't let a drop of fuel in, but again it is possible. I also wanted to ask are you making enough fuel pressure? Is the fuel pump circuit, the injectors, and the coil packs all on a run and start hot circuit? I've seen a few guys have problems where they didn't verify that you had current in both the run and start positions of the key. Also, ensure you have a super good ground on everything. You should have an Ohm or less of resistance between any ground and the negative battery terminal. I know Vettes use alot of fiberglass and such so I can imagine getting a proper ground might be a challenge.

Cover your basics. Is it getting fuel? (are the plugs wet or smell like gas) Does it have good spark (spark should be bluish not orange, indicates to me you have a weak ground or a weak positive connection or something) and does it have compression (this would be very apparent)

gMAG

iTrader: (1)

You can have fuel dribbling through the injectors, yet have no spray pattern. This can lead to no combustion/partial combustion.
It doesn't take much sitting around for the fuel to begin to gum up an injector.
VATS might still be an issue.

lizeec

iTrader: (57)

Need to eliminate the injectors as a cause for a no start condition, my suggestion was to try a squirt of starting fluid just to see if it will pop or fart, I would hope the OP is smart enough not to empty a can of starting fluid in the intake. But then again I see your point I've seen mechanics pressure wash a radiator.

C4 LS1

Ok as for the injectors I have already taken them off and cleaned them myself with gum out and seafood using an old fuel pump and hose with a switch I wired to pulse the injectors and they are all shooting plenty of gas now. I have visually watched the fuel injectors while cranking fire independentlty so I don't see fuel being a problem. I have not used starting fluid but ill give it a shot I'm thinking ill use two and a half cans or so lol I'm kidding. As for grounds I will check those tomorrow that might be my issue but I show the block has ground with my voltmeter however I will ohm it out.

umair

Connect an old spark plug to each of the lead one by one and crank it and see the color of the spark and if there is any.

C4 LS1

I did that and that is how I came up with having an orange spark all around. I am going to add more grounds just in case. You can never have enough grounds

LSCha0s

iTrader: (4)

Use a squirt of carb cleaner. starting fluid is ether and dangerous.

c6matt

iTrader: (1)

check for fuel pressure, and then look at your ecm voltage, if it drops below 11v cranking i've seen some weird behavior. make sure you have good power and ground.

badazz81z28

iTrader: (6)

Jon still seems to be out. I'm waiting for them to get back with me too

kossuth

iTrader: (12)

Your block being grounded is great, but the coil packs also have a ground wire I believe in conjunction with being bolted to the top of the valve cover. I know for sure the LS1 coils have a ground on each side, I suspect the newer fourth gen motors are the same. It might be getting a weak ground through the brackets and such, but if the wire is in the coil I imagine its there for a reason.

socal

iTrader: (1)

2nd the pop and fart w some carb clean, starting, brake clean, gas.
also pull an injector connector and connect a test light. the pink should be hot at all times and the other side should flash when turning the motor over

kossuth

iTrader: (12)

Also wanted to add, here is what your pinouts should be. Double check your low reference and your grounds. The low reference wire is basically a ground coming off the PCM so that it can tell what the resistance is across the circuit etc etc. Basically it should also be a ground when the key is on.

Drivers side


Passengers side

badazz81z28

iTrader: (6)

Keep in mind the OP is using PSI's harness...which is not exactly like factory. In fact talking with Jon at PSI, its proprietary on how the harness is wired.

OP, did you go through the trouble shooting tips on the last page of the manual?

"NO-START
1. Red Ignition Wire (From back of Fuse/Relay Center) has 12-volts with the Key in the ON position and CRANKING positions. This cannot be stressed enough, most NO-START conditions can be traced to this wiring issue.
2. Check Fuel Pressure for correct value (Approximately 58-psi).
3. Check that Fuel Injectors are firing. In many cases, engines which have been sitting for a few months have old fuel which has turned to varnish and clogged the injectors. A simple way to check if the injectors are clogged is to place a NOID LIGHT (Available at most autoparts stores) in the injector plug while cranking the engine. If the plug lights up, then the injectors are being commanded to fire. If the spark plugs are firing, the fuel pressure is correct, then the injectors are clogged and must be cleaned."

FAD2BLK93

How bout the crank position sensor, have u checked that?

moeZ28

iTrader: (7)

Not sure if PSI retains all of the LS1 harness grounds or not but on the back of the driver side head there is two wires, but 3 eyelets for grounds. If all 3 aren't grounded, the car will crank but not fire.

badazz81z28

iTrader: (6)

On my harness there are two grounds behind the driver head and two more inside on the ECM side of the harness